Tolerance vs. Acclimatization

In physical conditioning, typical training regimens disregard an important distinction between building exercise tolerance and becoming acclimated to exercise of a certain intensity.  Training at one extreme or the other can make the difference between failing to progress further in training and consistently progressing.

Exercise tolerance is one's capacity to withstand discomfort and push one's limits for short bursts.  Though this can be an important component of mental conditioning, one's limits are relative to their physical structure and metabolic function.  For example, when I was very young, my brother and I sought to improve our fitness by performing one set of burpees per day which increased by one repetition per day.  On day one, we both completed one burpee.  On day two, we completed two burpees, and so on.  This continued until we had reached 31 burpees in one set, or gave up.  I recall reaching 27 burpees and needing to quit due to a shoulder overuse injury.  For most individuals, this challenge sounds modest, even easy.  But for me at the end of my teenage years, this was the limit of my physical capacity.  I could only sustain this effort for 2-3 minutes, which means I would complete my repetitions and quit exercise for the day.  As a result, my body only adapted to the point of completing 2-3 minutes of hard exercise and no more.  Therefore, if I had continued to "work hard" by pushing myself at burpees, I would plateau at the same physical conditioning level and become optimized for 2-3 minutes of burpees at maximum, regardless of how difficult those 2-3 minutes would feel.

Acclimatization, by contrast, is the gradual shifting of one's latent exercise capacity, or the force one can produce comfortably and sustain over a long time.  This relates to deeper changes in metabolism and physical structure.  An example of this would be completing 1 burpee per minute for 5 hours.  In contrast to the primarily muscular effect of the 2-3 minute exercise tolerance sets, these sets would gradually shift one's physical constitution and metabolic resting state to be capable of a large volume of burpees at any instant.  The body would become better synchronized to that demand, and better results would emerge over sustained practice, such that eventually completing burpees would occur with the same effort as walking.  Eventually, completing 2-3 minutes of nonstop burpees would feel like a modest effort to an individual who has acclimated thoroughly to them.  Therefore, the best mindset for progress in physical conditioning is to make any movement of importance as effortless as walking.  Instead of striving to lift heavier weights, perform more repetitions faster, or go past the point of fatigue, one should make exceptional movements commonplace.  Examples of this include performing pushups, bear crawls, situps, and squats in high numbers without ever reaching muscular failure on a near daily basis.  This kind of training mimics my martial arts years where high amounts of these movements became a near daily ritual performed before and occasionally after work days with the same regularity and difficulty as tooth brushing.  I found results attained through this approach to be more sustained through periods of rest, even over weeks of minimal physical activity.  I've previously described this approach as the dying theory of muscle maintenance.  The downside to the long term adaptations produced by this kind of training is that not only the muscles adapt.  The organs and blood vessels also grow and thicken in proportion to one's muscular development, which can result in greater susceptibility to disease given an unhealthy diet (excess protein and fats beyond what the body requires).

The best balance is to train with high volume distributed over a long period of time and eat a mostly whole food, plant based diet to facilitate recovery.